1. Field of the Invention
The present invention relates to a semiconductor device for use in an inverter circuit for driving a motor or the like.
2. Description of the Related Art
A semiconductor device in which a transistor element such as a metal oxide semiconductor field effect transistor (MOSFET) element or an insulated gate bipolar transistor (IGBT) element is formed is known as a semiconductor device for use in an inverter circuit for driving a motor or the like. The semiconductor device according to the related art in which the MOSFET element is formed has a rectangular shape as viewed in plan. A source pad and a gate pad are formed on one surface of the semiconductor device. A drain electrode is formed on the other surface of the semiconductor device. The source pad is formed so as to cover substantially the entire surface of the semiconductor device. The gate pad is formed at one corner portion of the surface of the semiconductor device, or at the center portion of an edge portion along one side of the surface of the semiconductor device.
In the case where the semiconductor device in which the MOSFET element is formed is caused to function as an electronic circuit such as an inverter circuit, a plurality of semiconductor devices are mounted on a wiring substrate on which wiring is formed in advance. The semiconductor device is attached to the wiring substrate with a drain electrode of the semiconductor device joined to a drain metal pattern on the wiring substrate by solder. A gate pad of the semiconductor device is connected to a gate metal pattern on the wiring substrate by a connection metal member such as a bonding wire. A source pad of the semiconductor device is connected to a source metal pattern on the wiring substrate by a connection metal member. Connection through the connection metal member is achieved by a bonding device such as a wire bonding device (see Japanese Patent Application Publication No. 2001-102576 (JP 2001-102576 A), Japanese Patent Application Publication No. 2005-33073 (JP 2005-33073 A), Japanese Examined Patent Application Publication No. 5-63098 (JP 5-63098 B), and Japanese Patent Application Publication No. 2009-64995 (JP 2009-64995 A)).
When joining the drain electrode of the semiconductor device to the drain metal pattern using solder, the solder in the molten state may flow to rotate the semiconductor device on the metal pattern. In the semiconductor device according to the related art discussed above, in the case where the semiconductor device is rotated when joining the semiconductor device to the drain metal pattern, the positions of a region of the semiconductor device provided with the gate pad and a region of the semiconductor device provided with the source pad with respect to the drain metal pattern are varied. Then, the position of bonding the connection metal member to the gate pad and the source pad (the bonding coordinate set to the bonding device) must be corrected in accordance with the rotation of the semiconductor device, which reduces the bonding work efficiency.